Etiology of Radial Palsy

T he radial nerve is the most frequently injured of the three major peripheral nerves in the upper extremity.u It is most vulnerable to injury at the mid-humeral level, since it lies superficially and wraps around the spiral groove of the humerus. The most common causes of radial palsy are fractures of the humerus, elbow dislocations, and Monteggia fracture-dislocations. Barton states that one in every ten humeral shaft fractures is complicated by radial nerve palsy.! Neuropathy of the radial nerve is also frequently seen as a result of direct pressure from an external source, such as pressure in the axilla from a crutch or pressure over the nerve at the mid-humeral level (often referred to as Saturday night or drunkard's palsy). Although direct trauma is the most common cause of radial palsy, other etiological factors may cause the loss of radial nerve function, e.g., systemic disease such as diabetes mellitus, polyarteritis nodosa, alcoholism, and serum sickness; or the loss of function may result from a general neurological disorder. Dysfunction may also result from internal anatomical compression aSSOciated. with spontaneous compression syndromes or the-presence of a tumor.